Positioning system

ABSTRACT

A positioning system for a body comprises a flexible bag of a gas-impermeable material/including a valve to permit evacuation of the interior thereof, the bag containing a flowable granular material and at least one bolster. The body can be at least part of a human form, such as a patient. Systems are generally provided for specific body regions such as the hip or thorax, and for the whole body. The bolster is larger than the grains of the granular material. A size dimension of the bolster is therefore preferably at least 5 times the- size dimension of the granular material, although it sill usually be one or more orders of magnitude larger. Various forms of bolster are possible. A bolster that includes a generally flat section and an upstanding section extending therefrom can be used to locate a shoulder region of the patient in a reproducible yet comfortable form. A bolster that is generally cylindrical in shape can be used to support various areas of a patient such as the neck or knee. The granular material can consist of polystyrene spheres. The bag is preferably of a nylon material; such as a nylon material coated with a polyurethane-based coating.

This Application is a Section 371 National Stage Application ofInternational Application No. PCT/EP2007/006169, filed Jul. 11, 2007 andpublished as WO 2009/006925 A1 on Jan. 15, 2009, the content of which ishereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a positioning system.

BACKGROUND ART

Patient positioning systems are used for the accurate and reproduciblepositioning of patients for radiation therapy, diagnostic imaging,surgery and other medical procedures. For modern radiotherapytreatments, precise positioning of the patient is an indispensableprerequisite.

Typically, such positioning systems use a mouldable vacuum cushion inorder to combine patient comfort with reproducible accuracy of thepatient's position. The vacuum cushion consists of a hull material,typically a nylon cloth laminated with a polyurethane coating, a fillingmaterial such as polystyrene grains, and a valve.

In order to form the cushion into a mould, the patient is placed on thevacuum cushion which then deforms to a shape that accommodates thepatient. The tube is that connected to a vacuum supply such as one froma vacuum pump. This generates a vacuum in the cushion, and the vacuumcushion is moulded to the patient's contours. The grains that werepreviously free-flowing are constrained by compression resulting fromthe atmospheric pressure on the outside of the cushion.

Typical characteristics of such cushions include

-   -   reproducible positioning of the patient from imaging to        treatment and subsequent treatment fractions, while preserving        patient comfort and improving the clinical workflow    -   optimisation of clinical workflow for a range of clinical setups        and indications such as thorax, hip, full body and head and neck    -   a comfortable, stable and precise mould of the patient's        position

Such vacuum cushions are typically constructed entirely of radiotranslucent materials to provide consistent artefact-free image claritywith minimal dose attenuation.

A coated nylon material for the exterior of the cushion enables smoothmould definition, comfortable patient positioning and ease of cleaning.

SUMMARY OF THE INVENTION

The present invention therefore provides a positioning system for abody, comprising a flexible bag of a gas-impermeable material, includinga valve to permit evacuation of the interior thereof, the bag containinga flowable granular material and at least one bolster, which willgenerally be of a non- or semi-flowable material.

The body can be at least part of a human form, such as a patient.Systems are generally provided for specific body regions such as the hipor thorax, and for the whole body. The bolster is larger than the grainsof the granular material. A size dimension of the bolster is thereforepreferably at least 5 times the size dimension of the granular material,although it will usually be one or more orders of magnitude larger.

Various forms of bolster are possible. A bolster that includes agenerally flat section and an upstanding section extending there fromcan be used to locate a shoulder region of the patient in a reproducibleyet comfortable form. A bolster that is generally cylindrical in shapecan be used to support various areas of a patient such as the neck orknee.

The granular material can consist of polystyrene spheres with a generalparticle size of 0.5 to 3 mm.

The bag is preferably of a nylon material, such as a nylon materialcoated with a polyurethane-based coating.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described by way ofexample, with reference to the accompanying figures in which;

FIG. 1 shows a vertical section through a first embodiment of theinvention;

FIG. 2 shows a vertical section through a second embodiment of theinvention;

FIG. 3 shows a horizontal section through a second embodiment of theinvention;

FIG. 4 shows a vertical section through a third embodiment of theinvention; and

FIG. 5 shows a horizontal section through a third embodiment of theinvention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention generally adopt the structure of apatient positioning system as described above in relation to thebackground art, thus using mouldable vacuum cushion in order to positionthe patient comfortably in a reproducible manner. The vacuum cushionconsists of a hull material, typically a nylon cloth laminated with apolyurethane-based coating, together with a filling material such aspolystyrene grains. A valve is provided on the hull material in order toallow it to be evacuated through connection to a vacuum source or avacuum pump, or the like. Once evacuated, the atmospheric pressureacting on the hull material compresses the filling material therebypreventing further flow, and the positioning system adopts a rigid or asubstantially rigid state for so long as the vacuum is maintained. Whenthe vacuum is broken, the filling material once again becomes flowableand the vacuum cushion can be adapted to a different shape to conform toa new patient, for example. Once formed into the new appropriate shape,the whole material is again evacuated via the valve and the cushionbecomes rigid once again.

Embodiments of the present invention further include some form ofstructural component within the cushion, such as a knee cushion, a neckcushion or a shoulder retractor. As a result, moulding of the vacuumcushion to the patient's contour can be improved in respect of moulddefinition and shape rigidity through these predefined and integratedstructures. These also simplify the handling and moulding to thepatient's contour of the cushion as a result in a higher overall qualityof the moulding.

Generally, the structural components can be moved relatively freely inthe non-evacuated cushion. By evacuating the cushion, the structuralcomponents become a single unit together with the remainder of thecushion, due to the pressure of the filling material.

FIG. 1 shows one such example. The cushion 10 consists of a hullmaterial 12 and a filler 14, and also includes a plastics (and/ or fibrereinforced) shoulder retractor 16 generally shaped so as to include agenerally flat section 18 that extends underneath a patient's back, fromone end of which extends an upstanding part 20 that reaches up and overthe shoulder 22 of a patient 24.

With the cushion 10 in the non-evacuated state, the shoulder retractorand the patient can be positioned as required and the patient madecomfortable in the cushion. The cushion 10 can then be evacuated to“freeze” the shoulder retractor 16 in the required position. This willmean that, during treatment, the shoulders are held out of the beam andthe neck region can be stretched so as to result in improvedrepositioning of the tumour.

FIG. 2 shows an alternative arrangement. A cushion 50 includes a hullmaterial 52 and a filling 54, together with an integrated knee cushion56 of textile filled with polystyrene. This means that the knee or knees58 of the patient 24 are elevated during treatment, which is known tomove the rectum out of the beam in applications involving delivery ofradiotherapy to the pelvic region. FIG. 3 shows the cushion 50 fromabove, showing a generally rectangular region 56 which is thecylindrical knee cushion 56 from above.

FIG. 4 shows a third embodiment, in which the cushion 70 again includesa hull material 72 and a filling 74, in addition to a neck roll 76 thatis located within the cushion 70 so as to support the underneath of theneck 78 of a patient 24. This provides an additional stabilisation ofthe neck, which is not generally achievable with standard vacuumcushions given that there is little or no access beneath the patient'sneck in order to mould the cushion when the patient is lying on it. Thiscan serve to increase a patient's comfort during treatmentsignificantly, which will itself reduce movement of the patient, andcould also elevate the neck and shoulders so as to provide better accessfor the beam during treatment.

FIG. 5 shows the cushion 70 from above, and again a rectangular region76 can be seen indicating the generally cylindrical nature of the neckroll 76. As can also be seen in FIG. 5, the cushion 70 includes agenerally wider section 80 designed to accommodate the patient's torso,from which extends a tab section 82 of a generally narrower width tosupport the patient's head. The neck roll 76 is positioned generally inthe junction between the wider section 80 and the curved section 82 asit corresponds to the location of the patient's neck 78. However, itwill be appreciated that when the cushion 70 is not evacuated, the neckroll 76 will be moveable within the interior of the hull material 72 andtherefore this position will not be fixed.

The features of the above embodiments are not exclusive and could ofcourse be combined, for example to provide a cushion with a neck rolland a shoulder retractor. Equally, other forms of support could beprovided, including from specific supports such as lumbar supports andgeneral supports that can be moved around inside the hull in order toposition the patient as desired.

Various materials can be used for the cushion, but we prefer a nylonhull coated with a sealable polyurethane-based coating to provide thenecessary impermeability to gases that enables a vacuum to be maintainedover long periods of time. For the filling material, we preferpolystyrene spheres of a size typically between 0.5 and 3 mm. However,other materials can be adopted as desired.

It will of course be understood that many variations may be made to theabove-described embodiment without departing from the scope of thepresent invention.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. A positioning system for a body, comprising; a flexible bag of agas-impermeable material, including a valve to permit evacuation of theinterior thereof; the bag containing a flowable granular material and atleast one bolster positionable to support a part of the body.
 2. Thepositioning system according to claim 1 in which the body is at leastpart of a human form.
 3. The positioning system according to claim 1 inwhich the body is at least part of a patient.
 4. The positioning systemaccording to claim 1 in which a size dimension of the bolster is atleast 5 times the size dimension of the granular material.
 5. Thepositioning system according to claim 1 in which the bolster includes agenerally flat section and an upstanding section extending therefrom. 6.The positioning system according to claim 1 in which the bolster isgenerally cylindrical in shape.
 7. The positioning system according toclaim 1 in which the bolster comprises a flexible covering enclosing agranular material.
 8. The positioning system according to claim 7 inwhich the flexible covering is a textile material.
 9. The positioningsystem according to claim 1 in which the bolster is a moulded plasticstructure.
 10. The positioning system according to claim 1 in which thebolster is free to move within the bag when the bag is not evacuated.11. The positioning system according claim 1 in which the granularmaterial consists of polystyrene spheres.
 12. The positioning systemaccording to claim 1 claims in which the bag is of a nylon material. 13.The positioning system according to claim 12 in which the nylon materialis coated with a polyurethane-based coating.
 14. (canceled)
 15. Thepositioning system according to claim 4 in which the bolster includes agenerally flat section and an upstanding section extending therefrom.16. The positioning system according to claim 4 in which the bolster isgenerally cylindrical in shape.
 17. The positioning system according toclaim 16 in which the bolster comprises a flexible covering enclosing agranular material.
 18. The positioning system according to claim 17 inwhich the flexible covering is a textile material.
 19. The positioningsystem according to claim 16 in which the bolster is a moulded plasticstructure.
 20. The positioning system according to claim 19 in which thebolster is free to move within the bag when the bag is not evacuated.21. The positioning system according claim 20 in which the granularmaterial consists of polystyrene spheres.